This research proposal aims to investigate and define abnormalities in apoptosis and the removal of apoptotic cells in patients with Idiopathic Pulmonary Fibrosis (IPF). We hypothesize that abnormalities in apoptosis and apoptotic cell removal lead to increased TGF-beta 1 activity and contribute to the development of pulmonary fibrosis in this disease. There are two specific aims to this proposal: Specific Aim 1: To define abnormalities in apoptosis and apoptotic cell removal in IPF. Specific Aim 2: To determine the relationship between apoptosis, apoptotic cell removal and TGF-beta 1 production in IPF. Human monocyte derived macrophages, alveolar macrophages and lung fibroblasts will be obtained from subjects with IPF and normal age-matched controls. Apoptosis of these cells, and the ability of these cells to remove apoptotic cells will be determined. Apoptosis and apoptotic cell removal in IPF will be correlated with the degree of TGF-beta 1 production.